enzyme regulation

Question 1

substrate-level control acts on

Answer 1

a single reaction

Question 2

feedback control targets

Answer 2

a different step in the pathway

Question 3

activator ______ more products

Answer 3

promote

Question 4

inhibitors _____ more products

Answer 4

prevent

Question 5

strategies for enzyme regulation:

regulate the amount or availability (on/off switch)

Answer 5

temporal control of gene expression

protein degradation

enzyme compartmentalization

substrate availability

Question 6

strategies for enzyme regulation:

regulate the activity of the enzyme (volume control)

Answer 6

isozymes and isoforms

covalent modifications

allostery

Question 7

regulation of enzyme amount:

temporal control of gene expression (controlling gene expression of enzyme of interest)

Answer 7

regulation of chromatin remodeling

regulation of transcription

regulation of splicing and processing

regulation of transport out of nucleus

degradation of mRNA in cytosol

translational regulation

protein modifications

Question 8

regulation of enzyme amount:

protein/enyzme degradation

Answer 8

intracellular digestion in lysosomes (low pH and acid hydrolases degrade in lysosome)

proteasome

Question 9

regulation of availability:

enzyme compartmentalization

Answer 9

enzymes only acting in a specific location

Question 10

regulation of availability:

substrate availability

Answer 10

availability of 2nd messengers in signaling cascades

Question 11

regulation of enzyme activity:

isozymes and isoforms function to

Answer 11

catalyze the same reaction but with different efficiencies by mixing matching subunits: paralogs (gene duplication) and alternative splicing

also due to heterozygous alleles, monomer vs dimer/trimer etc, covalent modifications

Question 12

lactate dehydrogenase (LDH) participates in

Answer 12

lactic acid fermentation pathway

pyruvate (end product from glycolysis) + NAHD + H+ –> NAD+ + lactic acid

Question 13

LDH is a

Answer 13

tetramer (4 available isoform units)

Question 14

LDH 1 > 2

Answer 14

heart attack

Question 15

LDH 5 > 4

Answer 15

liver damage

Question 16

regulation of enzyme activity:

reversible covalent modifications

Answer 16

creates nonproteinogenic amino acids by adding 1 or more functional groups to activate/inactivate the enzyme

Question 17

reversible covalent modification:

lipids

Answer 17

myristoylation

farnesylation (farnesyl is an intermediate in cholesterol synthesis)

Question 18

reversible covalent modification:

nucleic acids

Answer 18

ADP ribosylation

Question 19

reversible covalent modification:

proteins

Answer 19

ubiquitination

Question 20

reversible covalent modification:

carbohydrates

Answer 20

greatest source of diversity to the proteome

Question 21

how are carbohydrates linked

Answer 21

O- or N- linkages

Question 22

reversible covalent modification:

small molecules- gamma-carboxylation

Answer 22

gamma-carboxylation

carbon linkage

Question 23

reversible covalent modification:

small molecules - sulfation

Answer 23

sulfation (oxygen linkages)

Question 24

reversible covalent modification:

small molecules - acetylation and methylation

Answer 24

acetylation and methylation

used a lot in histone modifications

Question 25

methyl groups can go on either

Answer 25

arinine and lysine (nitrogen linkages)

Question 26

acetyl groups can go on

Answer 26

lysine (nitrogen linkages(

Question 27

reversible covalent modification: small molecules - phosphorylation

Answer 27

oxygen linkages

Question 28

why is phosphorylation activating? thermodynamics: kinetics: cell processes: shape and charge complementarity:

Answer 28

thermodynamics: ATP hydrolysis (putting phosphate on) can drive unfavorable reactions- negative deltaG) kinetics: physiological processes dictate reaction rate cell processes: ATP amounts dictated by metabolism (energy charge); signal transduction amplification (catalytic turnover) shape and charge complementarity: each phosphate adds (-2) charge and has potential to make 3 H-bonds

Question 29

kinases

Answer 29

adds phosphates

Question 30

phosphatases

Answer 30

remove phosphates

Question 31

the name of a kinase indicates

Answer 31

on which amino acid the phosphate will be added onto e.g. serine kinases phosphorylate serine residues/amino acids

Question 32

regulation of enzyme activity: irreversible covalent modifications

Answer 32

proteolytic activation

Question 33

zymogen

Answer 33

enzymes that need to be cleaved to become active

Question 34

examples of zymogens

Answer 34

proteases (digestive enzymes, collagenase, and caspases) collagen blood clotting factors insulin/hormones

Question 35

regulation of enzyme activity: allostery: heteroallostery: homoallostery:

Answer 35

heteroallostery: effector binds at the allosteric site homoallostery: cooperativity

Question 36

example of allostery

Answer 36

ATCase in nucleotide metabolism

Question 37

binding of CTP perfers the

Answer 37

T/inactive state inhibition of ATCase

Question 38

binding of ATP prefers the

Answer 38

R/active state activation of ATCase

Question 39

LDH 1 =

Answer 39

H4

Question 40

LDH 2 =

Answer 40

H3M1

Question 41

LDH 3 =

Answer 41

H2M2

Question 42

LDH 4 =

Answer 42

H1M3

Question 43

LDH 5 =

Answer 43

M4